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L. VERGNIAUD.

PROCESS AND APPARATUS FOR THE MANUFACTURE OF CRUCIBL ES.

' APPLICATION FILED JULY 9, 1919.

1,392,541, Patenfed 0015.4,1921.

Inventor L. Veryni/a/ud,

By .W. We.

fittorney UNITED STATES PATENT OFFICE.

LOUIS VERGNIAUD, or PARIS, FRANCE, ASSIGNOR "r0 ETABLI'SSEMENTS JACOBHOLTZER, or PARIS, FRANCE, A CORPORATION.

PROCESS AND APPARATUS FOR MANUFACTURE OF 'CRUCIBLES.

1,392,541, Specification of Iietters latent. i

Patented Oct 4, 1921.

Application filed inly 9, 1919. Serial No. 309,594.

To all whom it may concern Be it known that. I, LOUIS VERGNIAUD, acitizen of the French Republic, residing at 43 Rue des Marais, Paris,France, have invented certain new and useful Improve ments in Processesand Apparatus for the Manufacture of Crucibles, of which the followingis a specificationu In the methods employed hitherto for the manufactureof crucibles by pressing a paste of clay or other substance, the saidpaste is placed in a metal mold having the shape of the desired crucibleand it is pressed by one or more mandrels which are arrangedconcentrically in relation to the mold and are forced successively intothe paste. The pressing is effected by means of a power press or byhand.

. In pressing by means of a power press the mandrel is forced graduallyinto the paste by moving either the mandrel or the mold by means of ascrew or a hydraulic ram,

but that method has the drawback that if the paste is comparativelystiff, the shaping of the paste doesnot takeplace uniformly and thepaste is liable to crack, while if the paste is very soft it is notcompressed suffi ciently to acquire the compactness that is requisite inorder to assurethat it shall have a long life when subjected to fireheat, and this drawback is particularly appreciable in the case ofcrucibles intended for use in melting steel or metal alloys of highmelting points. 1

In manufacturing by'hand, the mandrel is forced into the paste in adiscontinuous manner, that is to say, by successive impacts,- andgenerally a plurality of mandrels of differ ent and gradually increasingsections are employed in order that the successive shaping operationsthat are necessary to convert the solid clay block into the finishedcrucible shall be performed as regularly as possible; but since thiswork is done by hand the output is of course very low. Moreover as thecentering of the mandrel depends on the skill of the workman, it isfaulty and has the result that the walls of the crucible are not uniformin thickness and the crucible develops weaknesses. It has been proposedfor the purpose of guiding the mandrel which is struck by the workman,to provide the lower end of the mandrel with a stem that passes throughthe crucible. This arrangement however necessitates the formation of ahole in the bottom of the crucible,

which has to be stopped with a plug of clay after the crucible. isformed; but this plugging is difiicult and requires skill, and there isa difliculty in insuring a perfectly homogeneous and absolutely intimateincorporation of the bottom plug with the mass of the crucible.

.The present invention has for its object to provide an improved processwhich will avoid thosedrawbacks in the mechanical manufacture ofcrucibles, and more particularly of crucibles for melting steel, andalso an improved apparatus for carrying this improved process intoeffect by means of which the centering will be absolutely uniform andregular and the operation continuous.

The improved process. consists in using, for pressing the paste insidethe mold, a plurality of mandrels having the same or gradually differentsections, provided with perfectly centered and guided stems, upon whichblows are delivered successively by hammers of different lengths towhich a regular alternating motion is imparted by mechanical means; .thetotal length of each Figure 1 is an end elevation of a portion L of theapparatus- 1 Fig. 2 is an elevation showing the mandrels and the meansfor guiding same; and

' Fig. 3 is a plan'of the apparatus.

In. the illustrated example, the apparatus comprises three mandrels a,b, c of different and gradually increasing sections. The mandrels mayhowever be in any desired number and of equal sections without deyparting from the nature of the invention.

The crucible molds for the set of the three mandrels shown, are five innumber, and are mounted on a round plate d which is arranged to berotated around a vertical axle e. The clay paste is placed in each moldas it passes the point '1, and the charged mold is carried in successionunder the mandrels at 2, 3, 4, during which travel each of the mandrelsa, b, c is forced into the paste in a gradually increasing degree untilthe forcing in of the mandrel c situated at 4 has completed thefinished,internal shape of the crucible. \Vhen the crucible arrives at 5it is removed and taken to the drying place. Each mandrel has a stem 7whose head g is struck repeated blows by a hammer h. The total lengthsofeach of the mandrels a, Z), c and its respective stem 7 are differentand increase gradually from 2 to 4 in such a way that the same drivingof each of the stems of the mandrels by blows of the successive hammerswill force each mandrel in by an extent that increases along the points2 to 4. i

The hammers h are mounted atthe ends of the long arms of levers Z thatare lifted automatically aftereach'blow by the cams m of a wheel nrotating on a horizontal axis.

For the purpose of guiding the stems of the mandrels and centering thelatter accurately in the crucibles, one or more guide plates 2' aremounted slidably on the verti: cal axle eof the frame of the apparatus.

The stems work with slight friction in these guide plates whereby theyare guided and centered with absolute accuracy.

The improved apparatus allows of First, working with a comparativelystiff paste;

Second, reproducing in an absolutely regular and adjustable manner atwill the effects of the repeated blows of accrucible maker Working byhand with a mallet;

Third, effecting an absolutely regular centering of the mandrel, whiledispenslng 'with the hole in the bottom of the crucible for the passageof a guiding stein;

Fourth, employing any desired number of mandrels so that the finalshapeof the crucible may be produced as gradually as may be desired, sothat eachportion of the wall of the crucible may be subjected to auniform pressure;

F'fth, effecting the manufacture of the crucible in a continuous manner.7

Having now particularly described and set forth the nature of mysaidinventlon and in what manner the same is to be performed I declarethat what I claim is 1'. A process for forming crucibles consisting inplacing the material, from which the crucible is to be formed, in a moldmember and successively introducing mandrel members of successivelyincreasing sizes into the ma'terialin the mold, andmoving one of saidmembers relatively to the other member while a mandrel is in engagementwith said material for causing said material to be compressed. r

2. An apparatus for the manufacture of crucibles ofclay paste,comprising .on a fixed frame, guides wherein the stems of a series ofmandrels offdifferent lengths can slide, and are subjected to therepeated blows of hammers delivered .at adjustable regular intervals,whereby a gradual compression is exerted upon the paste constithecrucibles are formed'into aplurality of molds, simultaneouslyintroducing mandrels of successively increasing sizes into said molds orinto the material contained in the molds and bringing the material ineach mold successively into engagement with the mandrels of successivelyincreasing sizes.

5. An apparatus for producing crucibles including a turn-tableadapted tosupport a series of molds arranged incircular formation,'a series ofvertical guidesarranged above said molds, vertically reciprocatingshafts, slidably mounted in said guides,

mandrels of successively increasing sizes carried by said shafts anddesigned to enter said molds for compressing plastic material carriedthereby, and hammers engageable with the heads of said shafts forforcing'the mandrels downwardly into the material contained within themolds. LOUIS VERGNIAUD.

